Coupling of abiotic and biotic parameters to evaluate performance of combining natural lagooning and use of two sand filters in the treatment of landfill leachates.

A study in the Etueffont landfill, located in Belfort (France), was conducted to evaluate the performance of combining natural lagooning and use of two sand filters for treating leachates through the coupling estimation of several abiotic and biotic parameters. Two gravel filters were installed in the upstream of the first basin which communicates with the remaing 2, 3 and 4 basins. The distribution of physical-chemical (T, pH, Eh, EC, O2, SM, SO4(2-), Cl-, Zn, Fe, Mg, Ni, Al, As, Ba, Cu, Sn, Zn, BOD, COD, KN, NH4+, NO2+ ,TP, AOX: absorbable organic halides, VFA: volatile fatty acids, and atrazine) and biological (bacteria, protozoa, phytoplankton) parameters was assessed in the leachate entering in basin 1, and downstream of the filters. The results showed slight variations in the physical-chemical composition of the leachate between 1999 and 2000, most likely ascribed to the maturation of the landfill but a very significant removal of SM (suspended matter) by the sand filters. This, applied to the majority of the studied parameters. Thus, the sand filter treatment of the leachates combined with natural lagooning was efficient in the improvement of water clarification.

[Contribution of several physico-chemical tracers to the study of groundwater contamination by landfill leachates]. / Apport de certains traceurs physico-chimiques a l'étude de la contamination des eaux sosuterraines par les lixiviats de décharges.

This work deals with the estimation of the water content of several physico-chemical parameters in a landfill (Etueffont, Belfort, France), and their impact on the quality of the underground water. Samples were collected monthly from May 1998 to May 1999 with a vertical bottle, from the output of the landfill and from eight wells. The results showed high concentrations of most parameters in the well PZ30 and PZ3, situated near the landfill. The spatio-temporal distribution of the physico-chemical parameters (T, pH, EC, Eh, O2, Cl-, NO3-, SO4(2-), Na+, Ca2+, Mg2+, K+, Cu2+, Ni2+, Mn2+, Zn2+ and total iron) in the 8 wells was governed by geological, hydrogeogical, physical and chemical, and climatic factors. In addition, the concentrations of contaminants decreased in the last well (1 km from the landfill), indicating a purification and dilution effect. Nevertheless, we suspect short-term degradation of the groundwater in the Etueffont site.

Characterization of the Oum Er Rbia (Morocco) high basin karstic water sources by using solid state nuclear track detectors and radon as a natural tracer.

Uranium and thorium contents as well as radon alpha-activities per unit volume were evaluated inside different water samples by using a method based on calculating the CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs) detection efficiencies for the emitted alpha-particles and measuring the resulting track density rates. The validity of the SSNTD technique utilized was checked by analysing uranyl nitrate (UO2(NO3)26H2O) standard solutions. A relationship between water radon concentration and water transmission of different water sources belonging to two regions of the Middle Atlas (Morocco) water reservoir was found. The influence of the water flow rate as well as the permeability and fracture system of the host rocks of the sources studied was investigated.

The use of ivermectin for scabies.

BACKGROUND: Ivermectin, a modified avermectin, is widely known to be an ectoparasiticidal agent in animals but its effect on human ectoparasites is not known. METHODS: As a part of a chemotherapy trial with ivermectin against Wuchereria bancrofti microfilaraemia, two males with clinical scabies were studied. Three skin scrapings were taken from the lesions of each of the cases and examined with potassium hydroxide solution for the presence of eggs, larvae or adult mites. RESULTS: Following a single oral dose of ivermectin at either 100 micrograms or 20 micrograms/kg body weight both the itching and eruptions were reduced and the lesions healed after 14 days of treatment. Skin scrapings taken on days 7 and 30 after administering the drug did not reveal any mites. However, the lesions reappeared after 3 months. CONCLUSION: The beneficial results on the healing of scabetic lesions following ivermectin therapy indicates that the drug may have a scabicidal effect. Reappearance of the lesions may have been due to an inadequate dose. This emphasizes the need for future controlled trials on the efficacy of ivermectin against human scabies infection. If proven, this may be an additional advantage in mass chemotherapy campaigns, when there is co-existence of filariasis, intestinal helminthiasis and scabies.

Prevalence of lymphatic nodule in a bancroftian endemic population.

Prevalence and clinical manifestation of lymphatic nodule in natural course of bancroftian filariasis was evaluated in a representative population of 2837 of a defined endemic community of Orissa. Detailed clinical and parasitological examination of study subjects revealed high disease (35.6%) and mf rate (15.8%) and mean microfilariae density (GM: 15.3 +/- 5.1 per 60 mm3 of blood) in the community. Lymphatic filarial nodule was manifested in 216 (7.6%) subjects in different spectrum of filarial infection including endemic normals and asymptomatic mf carriers. Significant proportion of cases with acute filarial disease in the community manifested nodule. Significant proportion of cases with nodule had microfilaraemia (33.3%) as compared to that of community. However highest frequency of nodule was observed amongst microfilaraemics with lowest density of microfilaraemia in the community (P < 0.05.). This possibly indicates microfilariae clearance from circulation as a consequence of death of adult parasite. The above observations suggest that lymphatic nodules may manifest as an early and/or the only clinical sign of bancroftian filariasis. This might have been mediated through either the attempt of the immuno-competent host to kill the adult parasite in a similar fashion that is effected through DEC or by death of the mature parasite in its natural process of attrition.

Clinical filarial disease in two ethnic endemic communities of Orissa, India.

To evaluate the possible role of ethnicity in susceptibility to filarial infection, a comparative study of the prevalence of filarial infection was initiated in an endemic village inhabited by two ethnic populations of mainlanders and tribals. An age and sex matched sampled population of 591 mainlanders and 106 tribals was studied by detailed clinical and parasitological (60 mm3 blood) examinations. Sera collected from both population groups (26 each) matched for clinical stage of infection were analysed for humoral immune responses such as antifilarial IgG, circulating filarial antigen and immune complex level. The overall prevalences of clinical disease and infection in both mainlanders (34.18 and 14.4%) and tribals (25.47 and 17.9%) were comparable. However, both annual average adenolymphangitic attack rate (1.77 year-1) and the prevalence of chronic filarial disease (22.6%) amongst tribals were significantly lower. No true elephantiasis was observed in tribals. No significant difference was observed in their humoral immune response, although the antifilarial antibody of IgG class in all stages of filarial infection was lower in tribals than in mainlanders. The results did not reveal any difference in susceptibility to filarial infection in the ethnic groups. The paucity of progressive lesions observed in tribals possibly reflects a difference in the anatomy of lymphatics or genetic or immunoregulatory mechanisms, that needs further study.

The sheath of the microfilaria of Wuchereria bancrofti has albumin and immunoglobulin on its surface.

Using direct fluorescent antibody analysis it was shown that the sheath of live microfilariae of Wuchereria bancrofti has human albumin and the immunoglobulin G subclasses IgG1 and IgG4 on its surface.

Humoral immune response during filarial fever in Bancroftian filariasis.

Humoral immune responses against filarial parasitic infection were studied in 62 cases of acute filarial disease presenting with filarial fever with adenolymphangitis, in a community where Bancroftian filariasis was endemic, during and about one month before and after the febrile episode. Their total leucocyte and differential peripheral blood cell counts and anti-streptolysin O titre were determined and compared. Polymorphonuclear cellular responses and anti-streptolysin O titre did not show any significant alteration during and after fever. Three of 53 previously amicrofilaraemic subjects (9 of whom were initially microfilaraemic) had microfilaria in their circulation during fever, with a significant increase in their geometric mean microfilaria count. Titres of specific immunoglobulin (Ig) G and IgG4 antibody to Wuchereria bancrofti microfilarial excretory/secretory antigens (measured by enzyme-linked immunosorbent assay) decreased significantly during the fever and the lower levels were maintained one month after fever. The mean circulating immune complex level increased significantly during fever, and a significant percentage of cases demonstrated circulating filarial antigen during fever, which declined after one month, suggesting the release of filarial antigen into the circulation during fever which bound to antibodies to form immune complexes. These observations do not support the suggestion that bacterial infection is the aetiology of filarial fever. It is postulated that antigens released from parasites into the circulation during parturition by adult worms may evoke an allergic response in the host, causing periodic febrile episodes.

Ivermectin in the treatment of bancroftian filarial infection in Orissa, India.

Ivermectin treatment was evaluated for its efficacy and side reactions in sixty patients of Orissa with Bancroftian filarial infection and microfilaremia. Ivermectin was administered as a single oral dose at four dosage levels (20, 50, 100 and 200 micrograms/kg), and both microfilarial clearance and associated side reactions were monitored in a double blind fashion. Blood microfilariae were cleared in all patients at all dosages within 1 to 14 days. In most patients microfilariae reappeared by third month. The microfilaria appearance by third and sixth month averaged 12.2 to 44 percent of pretreatment values in the four study groups. Side reactions were encountered in almost all patients, the commonest being fever, headache, weakness, myalgia and cough which occurred most prominently 12 to 72 hours after treatment. Side reactions were more frequent and severe in patients with high microfilaria counts. Clinical reaction scores for each group were independent of the dose administered. The 200 micrograms dose group showed significantly more rapid microfilariae clearance and its delayed reappearance as compared with the other dosage groups and without inducing significantly greater clinical reaction scores.

Tropical pulmonary eosinophilia in an Orissa village.

BACKGROUND: Tropical pulmonary eosinophilia is usually seen in areas endemic for filariasis. It affects only a small proportion of the population at risk and microfilaria are rarely demonstrated in the peripheral blood. The actual prevalence of the tropical pulmonary eosinophilia syndrome has not been previously studied in an area endemic for filariasis. METHODS: We screened the population of a village in the Puri district of Orissa, where filarial infection is endemic, to determine the prevalence of tropical pulmonary eosinophilia by clinical examination measuring the absolute eosinophil counts, performing a chest X-ray and examining the stools for the presence of the parasite. Sera from symptomatic cases who had an eosinophil count above 2000 per cmm were further tested for filarial specific IgG and total IgE and the results compared with control sera obtained from 15 age- and sex-matched normal individuals. RESULTS: We were able to screen 1754 (91%) out of 1918 villagers who were more than 5 years old and found 69 cases who had typical clinical features of tropical pulmonary eosinophilia. Only 6 (0.34%) of these had eosinophil counts above 3000 per cmm and were considered to have the disease. Only 2 of the 6 had associated filarial lesions, one had microfilaraemia and 3 had typical chest X-ray changes. The mean (+/- SD) titres for filaria specific IgG (0.355 +/- 0.315 v. 0.120 +/- 0.092) and total IgE (0.455 +/- 0.316 v. 0.114 +/- 0.075) were significantly higher in cases with tropical pulmonary eosinophilia than in control subjects. The level of eosinophilia was related neither to the patients' immune status nor to the severity of the radiological lesions. All cases recovered after therapy with diethylcarbamazine. CONCLUSION: Tropical pulmonary eosinophilia is not uncommon in this community in Orissa where filariasis is endemic. However, the syndrome is rarely associated with clinical filarial lesions.

Tissue tonometry: a useful tool for assessing filarial lymphedema.

A tissue tonometer was used to assess peripheral lymphedema in patients with filariasis in a Bancroftian endemic community. Matched populations of 34 patients with Grade II and 29 patients with Grade III unilateral lower limb edema and 26 healthy subjects were assessed for leg tissue compressibility and circumference. Tonometry was performed at three fixed points on the leg using three weight levels (70, 140, and 210 gms). The mean value of compressibility for each weight level and points measured in the edematous leg were significantly less compared with the contralateral non-edematous leg in the filarial patients and the legs of healthy subjects. Patients with Grade III lymphedema were more resistant to compression than Grade II patients throughout the leg but especially at the foot. The least mean square analyses of circumference and compressibility differential values of edematous compared with non-edematous legs revealed a positive correlation at the foot in Grade II and the proximal and distal parts of Grade III lymphedema; moreover, the slopes were significantly different from zero. These findings support progressive tissue changes of edema and fibrosis first in the foot and later in the more proximal portions of the leg which correspond to progressive volume expansion with protein-rich fluid. Tissue tonometry appears to be a sensitive measure for assessing progression of both edema and fibroplasia in patients with peripheral lymphedema associated with filariasis, and, therefore, may be a useful tool to measure the efficacy of drugs commonly used to treat this condition.